Technical Field
The present invention relates to integrated circuit processing, and more particularly to filling high aspect ratio through holes with solder.
Description of the Related Art
Injection Molded Solder (IMS) technology utilizes a local vacuum function under a scanning head to effectively fill molten solder into an enclosed mold space, e.g., single-end via holes. Maintaining uniform and high vacuum conditions is difficult due to the scanning feature of the head. The head moves and needs to reseal to draw a vacuum over each hole to be filled. This method makes solder filling into high aspect via holes difficult and may result in slower throughput.